Pipe apparatus



Maia

April 13,

R. J. TROUT ETAL ,675,333

PIPE APPARATUS Filed Dc. 17, 1949 FIG. I.

INVENTORS RALPH J. TROUT CHARLES H. BHANNEN ATTORNEYS Patented Apr. 13,1954 PIPE APPARATUS Ralph J. Trout, Pittsburg, and Charles H. Brannen,Hayward, Calif., assignors to American Pipe and Construction 00., acorporation of Delaware Application December 17, 1949, Serial No.133,544

1 Claim. (Cl. 117-57) This invention has to do generally with the makingof centrifugally spun concrete pipe or pipe having a centrifugally spunconcrete lining.

In the art it is common practice to make concrete pipe and pipe having aconcrete or cementitious lining in a metal shell or casing byintroducing a slurry or wet mix of concrete or cement into a form suchas a metal shell and rotating the form to distribute the cementitiousmass evenly over the interior thereof. The form, which may or may notbecome a part of the completed pipe, is supported on and rotated byhorizontally disposed endless belts or bands which are driven by asuitable power source.

One of the problems in manufacturing such pipe has been the difficultyof removing the water from the slurry or mix as the water leaves thecompacting mass of cementitlous material and collects on the innersurface. In large diameter pipe the problem has been particularly acutein that large drops of water fall from the upper part of the pipepitting the surface below where they strike. While attempts have beenmade to brush the water out and to remove it by tipping the pipe, thesemethods have not proved entirely satisfactory. In many cases it wasfound necessary to scrape or trowel the lining smooth after such anoperation.

It is therefore an object of our invention to provide a novel improvedmethod of removing water from the concrete pipe or pipe lining while thepipe is spinning.

Another object is to provide such a method which is easy to carry outand which tends to improve the character of the interior finish of theplpe.

A further object is to provide such a method which requires nomechanical or physical contact of a brush or tool with the surface ofthepipe and which requires no tipping of the pipe or special manipulationthereof.

These and other objects will be apparent from the drawing and thefollowing description thereof.

Referring to the drawing:

Fig. 1 is a plan view, largely diagrammatic, of an apparatus forrotating the pipe and for carrying out the method of the invention;

Fig. 2 is an elevational view of the apparatus of Fig. 1;

Fig. 3 is a sectional view on line 3-3 of Fig. 1; and

Fig. 4 is a schematic or diagrammatic view of a modified form ofapparatus for carrying out the invention.

In a general way our method utilizes a moving stream of air for removingthe water from the pipe as the lining is formed. More particularlydescribing the invention, in Fig. 1 we show at H an apparatus which iscommonly used for supporting and rotating pipe or forms to be lined withconcrete. This apparatus includes a base I! upon which is mounted aplurality of sets of pulleys 15 over which extend belts I6. The beltsare driven by a motor I! through gearing l8 and shaft is which supportsthe endmost pulleys.

The pipe shell or form l2 which is usually 01' steel is cradled in theupper run 2| of the belts as shown in Fig. 2.

As the belt are driven the shell [2 is rotated and the desired liningmaterial of concrete or the like introduced into the shell as the sameis rotated. The pipe-supporting and rotating apparatus may include endthrust rollers 23 which are mounted for rotation about vertical axes andagainst which the ends of the pipe abut to prevent axial migration ofthe pipe.

In Fig. 3 the pipe shell I2 is shown provided with a cementitious lining25. As this lining is compacted during rotation of the shell the watermoves inwardly and gathers on the inner surface 26 of the layer 25.

In order to remove this water we introduce a strong current or blast ofair into the pipe at one end. This may be done by providing amotordriven blower unit 23 adjacent one end of the pipe. We prefer tolocate the blower to one side of the axis of the pipe and to provide theblower with a flexible hose 29 which may be adjustably positionedcentrally of the pipe to direct the stream of air axially of the pipe.With the blower unit located to one side, the hose 29 may be moved outof the way to permit the introduction of con crete slurry into the pipe,an operation which is usually accomplished by means of troughs which aremoved axially into the pipe and then inverted to dump their contents.

We have found that by causing a current of air to be passed through thepipe as the pipe is rotating, the water, as it accumulates on the innersurface of the cementitious lining, is forced along the pipe axiallythereof by the air. Some of the water flows out the end of the pipe. Atthe same time, considerable water is evaporated. Also, we have foundthat the quality of the lining is improved and that the surface thereofis much smoother than results from the conventional methods of makingthis type of pipe. By way of example, we have found that verysatisfactory results were obtained by passing approximately a 3 8000 C.F. M. of air through pipe of 36" diameter. In carrying out the processwe prefer to use relatively warm dry air in order to evaporate a largeproportion of the water from the cementitious mass as the water leavesthe mass during spinning of the pipe. In many geographical areasand-.undercertain weather conditions the atmospheric air present issuitable. However, there are many locations and many times when thehumidity of the air is relatively high and a when such is the case, weprefer to heat the air before passing it through the pipe. In- "Fig. 4of the drawing we show the apparatus forsaceomplishing this. In thisfigure, numeral t2 indicates the pipe, 28 the motor-driven blower unit.A conduit comprising the two sections '32 and 33 conveys air to the pipeafter the air has been 7 heated by passage through a heater '3 4. Any

conventional heat transfer device may he used. Although the inventionhas been particularly shown and described. it is contemplated thatvarious changes and modifications maybe made without departing iromthescope thereof as indicated by a the following claim.

We claim: I v In the manufacture of pipe having a cylindrical concretewall formed within a cylindrical metal shell, the steps of introducingwet concrete material into the shell, spinning the shell about itslongitudinal axis at a speed sufiicient V to spread and compact thematerial into a rela tively dense cylindrical layer within the shell,

and simultaneously removing water from the entireirmer 'surface o fith'e. layer iby passing air through the shell axially from end to endwhile the shell is spinning, the humidity of said ai being well belowthe saturation point. V

ReferencesCitedin the file of this patent BEN'IIEli)JSTATES PATENTS*Australia Aug. 28, I929

